Conventional Förster (or fluorescence) resonance energy transfer (FRET) configurations typically comprise two fluorescent dyes assembled into discrete pairs. Energy transfer is observed in a single step from the donor to the acceptor. This basic format is sufficient for many applications and is, by far, the most commonly reported in the scientific literature. Several commercial products (e.g., molecular beacons, TaqMan probes) also rely on discrete FRET pairs. More complex FRET configurations with multiple energy transfer steps have also been described, where energy is transferred from an initial donor to a terminal acceptor in n successive steps through n−1 intermediary dyes that act as both an acceptor (for the previous dye in the sequence) and donor (for the next dye in the sequence). The common feature of these configurations is that the FRET relays are designed to extend the range of energy transfer to distances greater than that allowed by the constraints of one-step FRET (i.e., >1.5-times the Förster distance, or typically >6 nm). As such, the configurations are typically linear, pseudo-linear, or otherwise comprise a sequential geometric arrangement where the excitation energy moves further out into space from its origin at the initial donor.